AGRTCULTT'RAT> BOTANY. 627 



622, 623). — Exi)erinieiits showed th.-it a pressure of 4 atmospheres of hydrogen 

 ill tlie presence of iioriual aiiiouiits of ox.v;,'eii liad no injurious effect on the life 

 of micro-orj;anisuis or on the activity of enzynis and toxins. A pressure of 4 

 atinosi)heres of oxygen or of carbon dioxid clieclied the development of micro- 

 orKauisrus. Their activity was checked in i)roportion to the superficial area of 

 the colonies. Compressed oxygen checked the activity of yeasts, but not their 

 cell-free alcoholic fermentation. Carbon dioxid under pressure checked both. 



The addition of reducing substances, such as glucose and soda, increased the 

 development of anaerobic organisms under i>ressures of 4 to ;"> atmosi)heres of 

 »»xygen. Sttrcina unntiitlnca was rendered colorless by this combination of con- 

 ditions. The addition of such materials to compress carbon dioxid was with- 

 out effect. 



The effect of dialysis on vegetable rennets, C. Gerbkr (CohhjI. Rend. Acad. 

 Sii. [I'aris]. 1)1 (l!)08). No. IJ,, pp. 601-603).— In a previous paper (E. S. R., 

 20. I). 20), the author called attention to the fact that in the juices of a number 

 of plants rennets were obtained which had the power of coagulating milk. In 

 the lU'esent paper he gives an account of investigations on the dialysis of the 

 juices of some jilants containing rennet, in which he found that when dialyzed 

 the juice obtained from a species of tig was 4 times less active and that from a 

 paper mulberry S times less active than the original sap. It was also found 

 that on precipitating the sap obtained from the osage orange and dissolving 

 the precipitate in a salt solution, the dialyzed liquid was 9 times as active as the 

 filtrate. The addition of a large amoimt of water to the plant juices had the 

 sjime effect as dialysis. 



Arsenic in vegetation exposed to smelter smoke, R. E. Sw.mn and W. D. 

 IIakkixs (.four. Atiicr. Chriii. Soc, 30 ilDOS), Xo. 6". pp. !)I.'>-!)2S) . — The basis 

 of the work described has been the vegetation of Deer Lodge Valley and ad- 

 jacent territory in Montana, particular attention being paid to hay and wild 

 grasses, as it was claimed that live stock were suft"ering from poisoning due to 

 rating grasses and hay that had grown in regions subject to smelter fumes. 



Hoth arsenic trioxid and coiiper were determined, and in some samples of 

 grass were obtained as high as 1,550 parts per million of arsenic trioxid and 

 1.S(K» i)arts of copper. In comi»arison the authors grew cereals in soil samples 

 that were taken outside of the range of smelter smoke. In no case did they find 

 more than 0.(M)f»2 i)er cent of arsenic trioxid in the mature plants, while as high 

 as o.Oiifl.'i Iter cent was obtained fr()ni grass grown on the same soil 5 miles 

 from the smelter but in the direction of the prevailing winds. Analyses were 

 made of :i number of other i»lants which showed that the large amomits of 

 arsenic trif>xid were deposited upon the plants and could not have been absorbed 

 from the soil. 



The results of the investigations showed very plainly that the greatest accu- 

 nnilation of arsenic occurred after the period of growth was ended and the ])lant 

 was dead. There was little doubt that the rains during the summer waslu'd 

 much of the arsenic from the vegetation, while in the winter the grass was 

 prote<-t«Ml by snow. That the arsenic is de|>osited rather than iibsorbed is shown 

 by the fact that l>y sluiking dry hay or grass grown in the vicinity of the 

 smelter, a finely- divided powder was obtained that was nnich higher in arsenic 

 than the grass from which it came. 



Comitarisons are given of analyses of grasses and other plants taken from the 

 vicinity of smelters in f»ther i)arts of the country. 



Effect of illuminating gas and ethylene upon flowering carnations, W. 

 Crockk.u and I.. 1. Kmciit (Hot. da:., ',r, (lUUS). Xd. J. /*/*. .!'>!)-27(i. /I'lis. .',). — 

 f»n account «if the conunon l)elief that |tlants do jioorly in houses lighted with gas 

 and beca\ise of various inquiries from carnation growers as to the eft"ect of illu- 



